Pterosaurs have wings formed from just their fourth finger but bats use fingers two, three, four, and five. Early pterosaurs were like Rhamphorhynchus and had a tail, but more advanced pterodactyloids lost their tails and had longer wrists.

There was a very small, bird-size Pterodactylus and a huge Quetzalcoatlus that had a wing span of 39 feet so it was the largest flying creature that ever lived!